There are many electrical appliances which could benefit from active as opposed to passive cooling but are either too small, or must remain too quiet, to incorporate an integral cooling fan. One example is the head-mounted high-intensity lamps currently used by surgeons and other medical/dental practitioners. Such assemblies, as the one depicted in U.S. Pat. No. 5,440,462, rely on a rather sophisticated housing to dissipate heat, since the incorporation of a fan would dramatically increase the weight of the lamp assembly, and might create noise that could distract the wearer.
Other examples of apparatus which could benefit from active cooling, but currently rely on passive heat dissipation due to size or noise requirements, include hand-held devices such as manual input devices for computers and hand-held telecommunications devices such as cellular telephones. In the case of the former, Microsoft Corporation of Bellevue, Wash. recently introduced a force-feedback joystick which includes its own processor and motors which need to be cooled. In this case, Microsoft incorporated a fan into the base of the unit, but users have found that the noise generated is unacceptable, in that it interferes with the quiet environment used to interact with the applications for which the device was intended.
In the case of cellular phones, users have found that through prolonged use, as in a vehicle, the unit becomes quite hot, often to an unacceptable degree. The heat generated by such phones conducts through plastic housing of the unit, which results in an unpleasant warming against the user's ear. As in the case of head-mounted medical/dental lighting, the interior of modern cellular phone packaging does not permit the integration of a cooling fan, which would also add weight and potentially introduce acoustic, if not electrical, noise.
In all of the cases just described, and there are others which will become obvious through the disclosure herein, a cable is already present to deliver power or to communicate other signals to the utilization device. In the case of the head-mounted medical/dental high-intensity light, a power cable runs either from a wall-mounted power supply or from the user's belt to provide electrical power to the lamp itself, which is typically halogen. In the case of the joystick, or other applications of this type, cabling must be provided from the base of the device to the computer not only for power, for also for signal communication. As for cellular telephones, although they may be used with internal batteries in a non-tethered state, when used in an automobile, often a power/charging cable is provided, which is the environment wherein such devices experience their prolonged use, leading to over-warming.